create unique index IX_account_unique_email on account_unique (email); alter table account_constrain add constraint unique_account_constrain_email unique(email); 1. 2. 同样往两张表中插入相同的数据都不能继续插入。 我们可以看到两个表,虽然功能都能达到,但采用的方法是不同的。 那么到底这两种方法有...
The UNIQUE constraint in PostgreSQL violated when more than one row for a column or combination of columns which have been used as a unique constraint in a table. Two NULL values for a column in different rows is different and it does not violate the uniqueness of UNIQUE constraint. When a...
create unique index idx_uniq_id_info_indext on index_t(id,info) ; maleah_db=# insert into index_t values (1,2,3,'test') ; INSERT 0 1 maleah_db=# select count(*) from index_t where id = 1 ; count --- 2 (1 row) 可以看到,可以插入id字段的重复值,在这种情况下,只能使用INCL...
then the UNIQUE constraint generates an error stating that the specified value already exists in the table. In PostgreSQL, a unique index is automatically created when we insert a UNIQUE constraint
constraint_type有四种:UNIQUE、PRIMARY KEY、CHECK、FOREIGN KEY 通过修改上边sql语句的table_name和constraint_type来进行相应的查询 警告
util.PSQLException: ERROR: duplicate key value violates unique constraint "xxl_job_info_pkey" 是主键冲突异常,每次插入数据时重新确认自增主键的取值,而是会使用缓存提高效率。 这就导致某些情况下插入数据(例如SQL语句中指定了ID)不会更新这个自增主键下一个取值的缓存,进而在下次插入时触发错误。 2 解决 代码...
Fixed issue of blocking of UNIQUE constraint/index on nullable column not implemented consistently. Fix a crash with T-SQL OPENQUERY() and four-part object name when T-SQL keywords are used as server name. Fixed the issue of update with TOP, OUTPUT and join failing with error ‘unrecognized...
CREATETABLEdevices ( device_idbigintprimarykey, device_nametext, device_type_idint);CREATEINDEXONdevices (device_type_id);-- co-locate the devices table with the events tableSELECTcreate_distributed_table('devices','device_id', colocate_with :='events');-- insert device metadataINSERTINTOdevic...
For example, if there's a unique constraint on a field such as a social security number, a user may not insert a duplicate row, meaning they can't access it, but they can deduce that a record with that social security number exists. By default, RLS is disabled on tables in ...
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